The present invention provides a new combination of topically active substances, for the prevention and alleviation of cell damage, caused by preservatives, detergents or drugs, used in topical pharmaceutical, cosmetic or veterinary compositions.
Many substances are applied topically to the skin or mucous membranes of humans or animals in order to alter the subject's appearance, to protect the subject from the environment, or to produce a biological change in the skin or other tissue for therapeutic, preventive or cosmetic purposes. These substances may generically be termed “topical products” and include such topically applied substances as cosmetics, over-the-counter and prescription topical drugs, and a variety of other products such as soaps and detergents.
Topical products occur in a variety of forms, including solids, liquids, suspensions, semisolids (such as creams, gels, pastes or “sticks”), powders or finely dispersed liquids such as sprays or mists. Examples of topical products commonly classified as “cosmetics” include skin care products such as creams, lotions, moisturizers and “treatment cosmetics” such as exfoliants and/or skin cell renewal agents; fragrances such as perfumes and colognes, and deodorants; shaving-related products such as creams, “bracers” and aftershaves; depilatories and other hair removal products; skin cleansers, toners and astringents; pre-moistened wipes and washcloths; tanning lotions; bath products such as oils; eye care products such as eye lotions and makeup removers; foot care products such as powders and sprays; skin colorant and make-up products such as foundations, blushes, rouges, eye shadows and liners, lip colors and mascaras; lip balms and sticks; hair care and treatment products such as shampoos, conditioners, colorants, dyes, bleaches, straighteners and permanent wave products; baby products such as baby lotions, oils, shampoos, powders and wet wipes; feminine hygiene products such as deodorants and douches; skin or facial peels applied by dermatologists or cosmeticians; and others. Examples of topical products commonly classified as “topical drugs” are many and varied, and include over-the-counter and/or prescription products such as antiperspirants, insect repellents, sunscreens and sunburn treatments, anti-acne agents, antibiotics, topical respiratory agents, ocular drugs such as eyedrops and saline solutions, therapeutic retinoids, anti-dandruff agents, external analgesics such as capsaicin products, topical contraceptives, topical drug delivery systems, gastrointestinal agents such as suppositories, enemas and hemorrhoid treatments, reproductive system agents such as vaginal treatments, oral treatments such as lozenges, and many other products with therapeutic or other effects. Other topical products include hand, facial and body soaps and detergents and other forms of skin cleansers, as well as household detergents and many other household products such as solvents, propellants, polishes, lubricants, adhesives, waxes and others which are either applied topically or are topically exposed to the body during normal use.
In a large number of cases topical products contain chemicals which may produce “irritation,” including various inflammation symptoms or signs, when applied to the skin or mucosa. The present invention is directed to compositions for inhibiting the irritation associated with such topical products.
The occurrence, frequency and nature of topical-product-induced irritation often varies from user to user. The severity of irritation to the susceptible user may range from subclinical to mild to severe. Typical symptoms of “irritation” include itching (pruritus), stinging, burning, tingling, “tightness,” erythema (redness) or edema (swelling). The irritation response may be due to the direct effect on the skin of certain topical product chemicals or to a response by the immune system directed toward the chemicals alone or in combination with skin components (e.g. antigens).
Many ingredients used in topical products are known irritants or are potentially irritating, especially to people with “sensitive skin”. These irritating ingredients include fragrances, preservatives, solvents, propellants and many other ingredients that might otherwise be considered inert components of the products. Additionally, many topical product active ingredients, including chemicals that may also be classified as drugs, produce irritation when applied to the skin. These include, but are not limited to, such ingredients as exfoliants and skin cell renewal agents, anti-acne drugs, antiperspirant compounds, antihistamines, anti-inflammatory agents, skin protective agents, insect repellent chemicals, sunscreens and many others. Where more than one chemical irritant is present, their irritating effects may be additive. Furthermore, chemical ingredients may react with one another, or in the environment of the skin, to form new chemicals which are irritating. The vehicles in which the active drug ingredients are formulated may also produce irritation in sensitive people.
Whatever the exact cause of irritation, many attempts have been made to reduce the irritation potential of topical products by identifying chemicals which tend to cause irritation and reducing their concentration or eliminating them from the products. Many of these products are advertised to consumers as “hypoallergenic” or the like to designate a product's reduced tendency to cause irritation in consumers with sensitive skin. Many skin and mucosal irritation responses, however, are not allergic in origin. In any event, it is often not feasible or practical to identify or eliminate all of the irritating chemical(s), particularly when the irritating chemical(s) are the active ingredient of the product or are required for formulation, preservative or other functional reasons.
It is an object of the present invention to provide an effective topical composition, for combating damaging effects of irritants to mucous and skin cells.
The present invention relates to topical compositions for combating damaging effects of preservatives or other irritants, found, e.g. in multi-dose eye drops, to mucous cells, especially in the corneal cells and simultaneously beneficial to those tissues. It was found that glycerol counteracts corneal cell damage caused by preservatives such as benzalkonium chloride, cetrimonium bromide, sodium ethylene diamine tetraacetate, etc. Not all the polyhydroxy compounds have such anti-irritant properties. Moreover, it is known that isotonic sodium chloride is toxic to the corneal cells, whereas isotonic glycerol is not toxic. (Follmann, P. et. al. Szemeszet 141, 305-308, 2004.)
In addition two physicochemical parameters are very important for a good topical composition: increased viscosity and increased spread of the solution.
Increased viscosity is achieved by high molecular weight (equal to more than 0.5 million Dalton) polymers. Increased spread is achieved by surface active agents, however after chronic use the surface active agents usually have damaging effects. (See Animal Studies, a).
It has now been found according to the present invention that all of the above mentioned problems of irritation by preservatives, detergents and other cell damaging agents disappear, and the beneficial effects are preserved or increased, by using a combination of xylitol, myoinositol or mannitol with glycerol and/or urea, preferably together with a surface active agent.
The advantages resulting from the addition of a surface active agent include a decrease in the surface tension of the aqueous solution, thereby increasing the spread. Thus it has now been found, that polysorbate 90 even at a concentration of 0.002% increases the diminished Break Up Time (BUT) in dry eye patients. (It is accepted that 10 sec. or less BUT indicates dry eye syndrome) (See Human Studies 1).
Thus, according to the present invention there are now provided topical pharmaceutical or cosmetic compositions for the prevention and treatment of irritation of mucous cells, or skin cells, comprising a combination of:
xylitol, myoinositol or mannitol or any combination of these;
glycerol and/or urea;
water;
in the absence of any oil in water or wax in water emulsion.
The present invention provides topical pharmaceutical or cosmetic compositions for the prevention and treatment of irritation of mucous cells, comprising a combination of:
1.5-5.5% xylitol, myoinositol or mannitol or any combination of these;
0.9-2.0% glycerol;
less than 0.01% inorganic salts;
water;
in the absence of any oil in water or wax in water emulsion.
The present invention further provides topical pharmaceutical or cosmetic compositions, for the prevention and treatment of irritation of skin cells, comprising a combination of:
5-18% xylitol, myoinositol or mannitol or any combination of these;
5-10% glycerol and/or urea;
water;
in the absence of any oil in water or wax in water emulsion.
More specifically the present invention preferably provides a non-irritant topical cosmetic or pharmaceutical composition for mucous cells or for the skin, as defined above, for the prevention of cell damage caused by preservatives, detergents or drugs in topically used cosmetic, pharmaceutical or veterinary compositions.
In especially preferred embodiments of the present invention there is provided a non-irritant topical cosmetic or pharmaceutical composition for mucous cells or for the skin, as defined above, further comprising at least one pharmaceutically active agent in solution, or in suspension but not in emulsion.
In preferred embodiments of the present invention there is provided a non-irritant topical cosmetic or pharmaceutical composition for mucous cells or for the skin, as defined above, further comprising at least one viscosity enhancing agent.
While the invention will now be described in connection with certain preferred embodiments in the following examples so that aspects thereof may be more fully understood and appreciated, it is not intended to limit the invention of these particular embodiments. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the scope of the invention as defined by the appended claims. Thus, the following examples which include preferred embodiments will serve to illustrate the practice of this invention, it being understood that the particulars shown are by way of example and for purposes of illustrative discussion of preferred embodiments of the present invention only and are presented in the cause of proving what is believed to be the most useful and readily understood description of formulation procedures as well as of the principles and conceptual aspects of the invention.